<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">
    <meta http-equiv="X-UA-Compatible" content="IE=Edge,chrome=1">
</head>
<body>
<!--<canvas id="content" width="1250px" height="602px"></canvas>-->
<canvas id="content" width="1980px" height="100px"></canvas>
</body>
</html>
<script>
    var cav = document.getElementById('content');
    var w = window.screen.width;
    var h = window.screen.height;
    var yPositions = Array(300).join(0).split('');
    var ctx = cav.getContext('2d');

    var draw = function(){


        ctx.fillStyle = 'rgba(0,0,0,.05)';
        ctx.fillRect(0,0,w,h);
        ctx.fillStyle = 'green';
        ctx.font = '20px';


        yPositions.map(function(y,index){
            text = String.fromCharCode(1e2+Math.random()*330);
            x = index*10;
            cav.getContext('2d').fillText(text,x,y);
            if(y>Math.random()*1e4){
                yPositions[index]=0;
            }else{
                yPositions[index]=y+10;
            }
        });


    }
    setInterval('draw()',30);
</script>